The present invention concerns a corrugated tube which is laid down in a state of accommodating a wire harness at the inside thereof along a vehicle panel or the like.
As shown, for example, in FIG. 2, an related corrugated tube 3 of this type comprising an elastic material in which a slit 4 is formed over the entire length of a cylindrical periphery of a flexible bellows-like tube main body having smaller diametrical portions 1 and larger diametrical portions 2 continuously formed alternately in the axial direction thereof has been known (for example, Patent Literature 1). In the corrugated tube 3 described above, the slit 4 at one end is dilated to form an opening, a wire harness 5 is inserted to the opening and then the corrugated tube 3 is moved in the direction of an arrow in the drawing so as to move slidably at the outer peripheral surface of the wire harness 5, thereby gradually accommodating the wire harness 5. Then, after accommodating the wire harness 5 as far as the other end of the slit 4, the slit 4 is kept in a closed state by the resiliency of the tube main body and the wire harness 5 is kept in the accommodated state without protruding from the corrugate tube 3.
However, since a synthetic resin, for example, a polypropylene which is rigid to some extent is used as the elastic material for protecting the wire harness 5 accommodated therein, the outer skin of electric wires that constitute the wire harness 5 may sometimes be in contact with the open end edge of the slit 4 and injured during the accommodating operation as shown by a cross sectional view perpendicular to the axial line in FIG. 3.
In view of the above, as shown in FIG. 4 (drawing on the right is a front elevational view as viewed from the side in which the slit 4 is formed and the drawing on the left is a left side elevational view thereof), a corrugated tube 3 is proposed in which a soft portion 10 comprising a rubber material (ethylene propylene rubber: EPDM) with Shore A Hardness of about 35 to 50 (ethylene propylene rubber EPDM) is formed on both ends of the slit 4 over a predetermined peripheral width is formed (for example, Patent Literature 2).
However, since the frictional resistance of the slit portion 4 is large in the corrugated type tube 3 described above, this results in a problem that sliding movement with the wire harness 5 does not proceed smoothly in the accommodating operation to make in the operation efficiency poor.    Patent Literature 1: JP-UM-A-62-16888    Patent Literature 2: JP-A-2000-287331